Thank u vеry much. In regard to const char * type, i use it just a stupid c-strings, caz i need maximum performance. p.s. In my app keys are immutable. On Wed, Dec 31, 2008 at 05:02, Robert Ramey <ramey@rrsd.com> wrote:

Anytime you're serialization a "const" value its a red flag that you might really want to do that. "const" values are initialized when the object is created and should never subsequently change.

anyway, try:

save .. ar << data.count();. for (iter = data_.begin(); iter != data_.end(); iter++) { std::string key(iter->first); ar << key; ar << iter->second; }

load ... _data.clear() ar >> count; while(0 < count){ std::string key; int i; ar >> key; ar >> i; data_.insert( key.cstr(), // of course this won't work - but you get the idea i ); }

Robert Ramey

Denis Gabaidulin wrote:

...

I have following class with stl container:

class storage : { private: map<const char*, int, cmp> data_;

friend class boost::serialization::access;

template<class Archive> void save(Archive & ar, const unsigned int version) const { map<string, int> local; constDataIter iter;

for (iter = data_.begin(); iter != data_.end(); iter++) { local[iter->first] = iter->second; }

ar & local; } }

This code works, but it slowly(full copy) and consume too much memory (x2) :-(

What is the best serialization strategy with such stl containers or pointer to pod type?

I cannot change const char* to string, dont ask me why :-))

Thanks you for any advice.

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On Wed, Dec 31, 2008 at 19:41, Robert Ramey <ramey@rrsd.com> wrote:

...

Thank u vÅry much.

In regard to const char * type, i use it just a stupid c-strings, caz i need maximum performance. p.s. In my app keys are immutable.

Then why are you storing them in a file? That's the red flag.

My app is something like memcached daemon, but with addiotional commands flush/load for dumping current state to persistent storage(disk).

On Wed, Dec 31, 2008 at 20:53, Robert Ramey <ramey@rrsd.com> wrote:

...

...

...

Thank u vÅry much.

In regard to const char * type, i use it just a stupid c-strings, caz i need maximum performance. p.s. In my app keys are immutable.

Then why are you storing them in a file? That's the red flag.

My app is something like memcached daemon, but with addiotional commands flush/load for dumping current state to persistent storage(disk).

Since you're concerned about performance, why are you storing immutable data?

I store current state of storage (just serialize all elements of map) for backup. If daemon segfaults of even server reboot, daemon lose only data since last flush commad was. So, typical usage of daemon: E.g. Another app(adv. rotation system) have some counters(impressions today, impressions total, clicks today, etc). Many process set/get/inc/dec many counters. Each process communicate with daemon using simple textual protocol(i know that binary faster, but textual more useful for my purposes). map[immutable key] = value; Key never change, but value can.

so why store the key?

eg

const char * keytable[] { "key1", // store keys at compile time in order "key2", ... }

I have no data in compile time. Data storage fill at runtime. Some keys could be inserted or deleted, *values* could be updated(increment/decrement/set), but there is no way one can any key could be changed, therefore key is immutable. Its very similar to memcached daemon.